This invention relates generally to a particle reclaim system, and more particularly, a brush auger that reclaims toner through filtration in a photoreceptor cleaner housing.
A system for automatically recovering residual toner and returning it to the developer housing for reuse in the development zone is described in U.S. Pat. No. 3,752,576 and U.S. Pat. No. 3,678,896 in which an endless bead chain conveyor moves between the cleaning station and the development station of a xerographic system. As provided in the cleaning systems shown in the aforementioned patents, toner cleaned from the xerographic plate at the cleaning station is moved from the cleaning station to the developer station by means of a development unit for reuse in the development process.
It has been found that toner returned to the development unit in such systems often contains contaminants and foreign matter such as paper fibers, brush fibers, metal chips, and pieces of foam which if not removed are automatically transported back to the developer housing by the above noted bead chain system. Such foreign particles often jam up the bead chain system thus necessitating cleaning or replacement of the unit in the field. If the particles pass through the bead chain conveyor system, they are returned to the developer housing and may have an adverse effect on the quality of the development system. As developer life increases, the percentage of foreign particles being constantly recirculated within the machine in the aforementioned manner gradually increases and the deleterious effects thereof become more aggravated. The only removal of contaminants under the present system occurs when either the developer is changed or the toner return system is removed and cleaned or replaced.
The reclaiming of toner removed from the photoreceptor (i.e. imaging surface) after transfer by the cleaner has been a desirable copier feature for a long time. In the past several copier programs have had toner reclaim as a mainline feature only to remove the reclaim capability late in the program development because of problems with copy quality. It is now generally accepted that some type of toner clean-up is required before used toner can be recycled back to the development housing. The rationale for this point of view is that large agglomerates of toner, paper debris and other contaminants can cause poor development and/or transfer problems. Some of the reclaimed toner may also have inherent properties which make it difficult to charge properly in the development housing or transfer to paper easily. It is an objective of this invention to remove such large agglomerates from the toner before it is returned to the developer housing.
Other toner reclaim methods have utilized a brush auger device of stiff material to screen out large particles from the cleaned toner before it is returned to the developer housing. The stiff fibers in contact with the mesh screen create high torque on the toner reclaim system. It is an objective of the present invention to reduce the torque on the system. It is also an objective of the present invention to enclose the auger reclaim system in the cleaner housing to utilize less space. A further objective of the present invention is to increase the reclaim efficiency of the toner.
The following disclosures may be relevant to various aspects of the present invention and may be briefly summarized as follows:
U.S. Pat. No. 4,870,465 to Lindblad et al. describes a toner removal apparatus employing an auger member for abrading a charge retentive surface such as a photoreceptor so that excess toner is removed. The apparatus is used in conjunction with a blade so that all toner particles are removed and simultaneously transported away from an imaging area. The abrading action of the auger aids in the removal of large paper particles and other impurities which can accumulate on the photoreceptor.
U.S. Pat. No. 4,752,805 to Fukae et al. describes a device for recycling residual developer particles which are removed from a photoconductive element by a cleaning unit in an electrophotographic machine or printer. The apparatus uses a system of perforated tubes and brush augers to transport and distribute the toner particles to a developing unit. A rotating brush auger is adjacent to a first tube and transports the released particles into the first tube. A second auger is embodied within a second tube which aids in the transport and even distribution of the particles within the developer unit. The second tube is perforated with holes that increase in diameter as one travels further away from the second tube. Thus, the residual toner is evenly distributed within the developer unit so that clear copies can be obtained.
U.S. Pat. No. 4,319,832 to Sakamoto et al. describes a toner separation and recovery apparatus which uses a cylindrical electrode to attract the oppositely charged toner particles, after which a blade scrapingly deposits them into an adjacent toner recovery chamber. A fur brush removes residual toner and foreign matter from a photoconductive drum and creates an air flow which carries the particles through a passageway where the foreign matter is deposited into a chamber while the toner adheres to the charged electrode.
U.S. Pat. No. 4,213,794 to Wooding et al. describes a cleaning apparatus having a rotating brush which removes residual toner particles from an imaging surface and an auger comb which transports the particles along a path to a collecting station for vacuum removal. The comb facilitates the removal of the toner particles from the cleaning unit as well as the transportation of the particles to a disposal system.
U.S. Pat. No. 4,054,381 to Bernhard describes a filter arrangement adapted for use in a cleaning station of an electrostatographic reproduction machine which removes foreign particles and other undesirable contaminants from residual toner prior to its collection in a reuse container. A screw type brush is located within a housing having a mesh screen and serves to transport the residual toner over the screen to separate it into size components. The large particles are collected in a waste container while the smaller particles are filtered into a recycle container.